1. Salient pole type alternators are generally used on (a) low voltage alternators (b) hydrogen cooled prime-movers (c) high speed prime-movers (d) low and medium speed prime-movers 2. Turbo-alternators are generally used to run at (a) 500 R.P.M. (b) R.P.M. (c) 5000 R.P.M. (d) 16000 R.P.M. 3. The rotor preferred for alternators applied to hydraulic […]
1. The circle diagram for an induction motor cannot be used to determine (a) efficiency (b) power factor (c) frequency (d) output 2. Blocked rotor test on induction motor is used to find out (a) leakage reactance (b) power factor on short circuit (c) short-circuit current under rated voltage (d) all of the above. 3.
1. The frame of an induction motor is made of carbon (a) closed grained cast iron (b) aluminium (c) stainless steel 2. Slip rings for induction motors are made of (a) phosphor bronze (b) aluminium (c) carbon (d) cobalt steel 3 . If ‘s’ is the slip and ‘f’ is the supply frequency, the frequency
1. In induction motor, percentage slip depends on (a) supply frequency (b) supply voltage (c) copper losses in motor (d) none of the above 2.The efficiency of an induction motor ……….is than that of a transformer. (a) lower (b) higher (c) either of the above (d) none of the above 3.If the rotor circuit of
1. In a megger when not in operation, the needle shows a resistance of (a) Zero ohms (b) Infinity (c) 100 ohms (d) 500 Ohms 2. A cadmium sulphide cell is a (a) solar cell (b) dry cell (c) photo voltaic cell (d) photo conductive cell. 3. A photo electric transducers are used for the
1. Bolometers are used for the measurement of (a) optical inputs (b) thermal radiations (c) electrical signals (d) temperature inputs. 2. A bolometer is an element which (a) senses optical input and delivers thermal output (b) senses thermal inputs (c) senses electrical input and delivers thermal output (d) senses optical input and delivers electrical output.
1. A pointer of an instrument once deflected returns to zero position, when the current is removed, due to (a) action of gravity (b) mass of the pointer (c) controlling torque (d) damping torque 2. An instrument in which the value of electrical quantity to be measured can be determined from the deflection of the
1. In which of the following cases shunt capacitance is negligible ? (a) Short transmission lines (b) Medium transmission lines (c) Long transmission lines (d) All transmission lines 2. A lightning arrester is usually located nearer to (a) transformer (b) isolator (c) bus-bar (d) circuit breaker (e) none of the above 3. The material used
1. Which of the following has least effect on corona ? (a) Atmospheric temperature (b) Number of ions (c)Site and charge per ion (d) Mean free path 2. In context of corona, if the conductors are polished and smooth, which of the following statements is correct ? (a) Hissing sound will be more intense (b)
1.For aluminum, as compared to copper, all the following factors have higher values except (a) specific volume (b) electrical conductivity (c) co-efficient of linear expansion (d) resistance per unit length for same cress-section 2.Which of the following equipment, for regulating the voltage in distribution feeder, will be most economical ? (a) Static condenser (b) Synchronous